package com.atlassian.plugin.util;
   
   import com.atlassian.plugin.Application;
   import com.google.common.base.Function;
   import com.google.common.base.Objects;
   import com.google.common.base.Predicate;
   import com.google.common.collect.ImmutableList;
   import com.google.common.collect.Iterables;
   import com.google.common.collect.Sets;
  import org.apache.commons.lang.StringUtils;
  import org.dom4j.Element;
  
  import java.util.List;
  import java.util.Set;
  
  import static com.google.common.base.Preconditions.*;
  import static com.google.common.collect.Iterables.*;
  import static com.google.common.collect.Iterables.transform;
  import static com.google.common.collect.Lists.*;
  
  /**
   * Represents a list of {@link ModuleRestrict}. This represents the restricts
   * as used in the plugin descriptor:
   * <code><br>
   * &nbsp;&nbsp;&lt;module key="module-key"><br>
   * &nbsp;&nbsp;&nbsp;&nbsp;&lt;restrict ...>...&lt;/restrict><br>
   * &nbsp;&nbsp;&nbsp;&nbsp;&lt;restrict ...>...&lt;/restrict><br>
   * &nbsp;&nbsp;&lt;/module>
   * </code>
   *
   * @since 2.14.0
   */
  final class ModuleRestricts
  {
      final Iterable<ModuleRestrict> restricts;
  
      private ModuleRestricts()
      {
          this(ImmutableList.<ModuleRestrict>of());
      }
  
      private ModuleRestricts(Iterable<ModuleRestrict> restricts)
      {
          this.restricts = ImmutableList.copyOf(restricts);
      }
  
      static ModuleRestricts parse(Element moduleElement)
      {
          final String applicationKeys = moduleElement.attributeValue("application");
          if (applicationKeys != null)
          {
              return parseApplicationsFromAttribute(applicationKeys);
          }
          else if (!moduleElement.elements("restrict").isEmpty())
          {
              @SuppressWarnings("unchecked")
              final List<Element> restrict = moduleElement.elements("restrict");
              return parseApplicationsFromRestrictElements(restrict);
          }
          else
          {
              return new ModuleRestricts();
          }
      }
  
      private static ModuleRestricts parseApplicationsFromRestrictElements(List<Element> restrictElements)
      {
          final Set<String> definedApplications = Sets.newHashSet();
  
          return new ModuleRestricts(Iterables.transform(restrictElements, new Function<Element, ModuleRestrict>()
          {
              @Override
              public ModuleRestrict apply(Element restrictElement)
              {
                  final String application = restrictElement.attributeValue("application");
                  checkState(application != null, "No application defined for 'restrict' element.");
                  checkState(!definedApplications.contains(application), "Application '" + application + "' is defined at least twice. Only one definition allowed!");
                  definedApplications.add(application);
                  return new ModuleRestrict(application, parseVersionRange(restrictElement));
              }
          }));
      }
  
      private static VersionRange parseVersionRange(Element restrictElement)
      {
          final String version = restrictElement.attributeValue("version");
          if (version != null)
          {
              return VersionRange.parse(version);
          }
          else
          {
              final List<Element> versionElements = restrictElement.elements("version");
              if (!versionElements.isEmpty())
              {
                  VersionRange range = VersionRange.empty();
                  for (Element versionElement : versionElements)
                  {
                      range = range.or(VersionRange.parse(versionElement.getText()));
                 }
                 return range;
             }
             else
             {
                 return VersionRange.all();
             }
         }
     }
 
     private static ModuleRestricts parseApplicationsFromAttribute(String applicationKeys)
     {
         final String[] keys = applicationKeys.split("\\s*,[,\\s]*");
         final Iterable<ModuleRestrict> restricts = transform(filter(newArrayList(keys), new IsNotBlankPredicate()), new Function<String, ModuleRestrict>()
         {
             @Override
             public ModuleRestrict apply(String app)
             {
                 return new ModuleRestrict(app);
             }
         });
 
         return new ModuleRestricts(restricts);
     }
 
     public boolean isValidFor(Set<Application> applications)
     {
         if (Iterables.isEmpty(restricts))
         {
             return true;
         }
 
         for (Application application : applications)
         {
             if (Iterables.any(restricts, new RestrictMatchesApplication(application)))
             {
                 return true;
             }
         }
         return false;
     }
 
     @Override
     public String toString()
     {
         return restricts.toString();
     }
 
     static final class ModuleRestrict
     {
         final String application;
         final VersionRange version;
 
         ModuleRestrict(String application)
         {
             this(application, VersionRange.all());
         }
 
         ModuleRestrict(String application, VersionRange version)
         {
             this.application = checkNotNull(application);
             this.version = checkNotNull(version);
         }
 
         @Override
         public String toString()
         {
             return Objects.toStringHelper("restrict")
                     .add("application", application)
                     .add("range", version)
                     .toString();
         }
     }
 
     private static final class IsNotBlankPredicate implements Predicate<String>
     {
         @Override
         public boolean apply(String input)
         {
             return StringUtils.isNotBlank(input);
         }
     }
 
     private static final class RestrictMatchesApplication implements Predicate<ModuleRestrict>
     {
         private final Application app;
 
         public RestrictMatchesApplication(Application app)
         {
             this.app = checkNotNull(app);
         }
 
         @Override
         public boolean apply(ModuleRestrict restrict)
         {
             return restrict.application.equals(app.getKey())
                     && restrict.version.isInRange(app.getVersion());
         }
     }
 }